(1) Field of the Invention
The present invention relates generally to hazard alarms, and more particularly, to a communication system for interconnecting multiple alarms and/or other hazard alarms into a system (e.g. a smoke and carbon monoxide alarm system).
(2) Background Information
Hazard alarm systems are well known. Typical alarm systems include smoke, carbon monoxide (CO), gas, heat, intrusion (e.g., motion) detection, and the like. Substantially all new construction, whether residential or commercial, includes one or more of these systems. Of particular importance for residential dwellings are smoke and CO alarm systems, which detect two of the principle life-threatening hazards associated with home heating: smoke; and CO emissions; respectively.
Smoke and CO alarms have often been self-contained units (i.e. units that include both hazard detection circuitry and an alarm indicator such as a horn or buzzer) that may be placed wherever necessary for the protection of a dwelling. It is generally desirable for numerous reasons, not the least of which is compliance with the U.S. National Fire Code, to electrically connect such self-contained hazard alarms together into a system such that when any one detector is activated all of the detectors sound an alarm.
Albinger, et al., in U.S. Pat. No. 4,223,303, discloses a connection system for connecting a plurality of alarm devices such that an alarm condition (e.g. the detection of a critical level of smoke in a smoke detector) in any one of the alarm devices causes all other alarm devices to generate an alert. No provision, however, is provided for alarm devices of different types. Therefore, in the event smoke and CO alarms, for example, were connected together in this type of system, the detection of smoke in one device would generally cause all detectors, whether smoke or CO detecting devices, to generate an alert. This condition may result in confusion as to the type of hazard and is therefore generally undesirable.
There therefore exists a need for an improved alarm system, enabling multiple hazard device types (e.g. smoke and CO) to be interconnected in a manner such that each hazard device type may generate an alarm signal capable of triggering alarm indicators in other devices of the same type, without triggering alarm indicators associated with any other device types.
One aspect of the present invention includes a hazard alarm for use in a hazard alarm system. The hazard alarm includes an interface circuit, a first type sensor coupled to the interface circuit, and an alarm indicator coupled to the sensor. A transmitter is coupled to the interface circuit to generate a first type signal in response to a first type alarm event detected by the first type sensor, the first type signal being receivable by at least one other hazard alarm connected thereto to trigger a first type alarm indicator therein, while not triggering any second type alarm indicator connected thereto. A signal receiver is operatively coupled to the interface circuit to receive first type signals and second type signals, and to selectively actuate and not actuate the first type alarm indicator upon respective receipt thereof.
A variation of this aspect includes a system of the hazard alarms being interconnected to one another.
In another aspect, the present invention includes an alarm system including: a plurality of hazard alarms including a plurality of first type hazard alarms and a plurality of second type hazard alarms. Each one of the plurality of hazard alarms includes at least one interconnect port. The first type hazard alarms include an interface circuit coupled to the interconnect port to respectively transmit and receive information with others of the plurality of hazard alarms interconnected thereto. The interface circuit is configured so that an alarm event in any one of the first type hazard alarms triggers an alarm indicator in at least one other of the first type hazard alarms interconnected thereto, while not triggering an alarm indicator in any of the plurality of second type hazard alarms interconnected thereto. The interface circuit receives and transmits digital information at a bit rate of greater than about 100 bits per second.
In another aspect, the present invention includes an interface circuit for a hazard alarm used in an alarm system. The interface circuit includes an input protection portion including at least one input protection component selected from the group consisting of a metal oxide varistor and a zener diode; a high pass filter portion including a transistor; and a signal amplifier portion including a low pass filter coupled to an other transistor.
In still another aspect, the present invention includes a kit for upgrading a smoke alarm system including a plurality of smoke alarms electrically connected to one another. The kit includes a plurality of carbon monoxide alarms, each of the carbon monoxide alarms including at least one interconnect port, and an interface circuit coupled to the interconnect port to communicate information with other hazard alarms interconnected thereto. The carbon monoxide alarms also include a sensor coupled to the interface circuit to detect an alarm event, an alarm indicator coupled to the sensor, and a transmitter coupled to the interconnect port to generate a first signal type in response to the alarm event. The first signal type is receivable by at least one other carbon monoxide detector to trigger an alarm indicator therein, while not triggering an alarm indicator in any smoke alarms connected thereto. A signal receiver is operatively coupled to the interconnect port to receive signals of the first and a second signal types, and to selectively actuate and not actuate the alarm indicator upon receipt of signals of the first and second types, respectively.
In a further aspect, this invention includes a method of fabricating a hazard alarm for use in a hazard alarm system. The method includes providing an interface circuit, and coupling a first type sensor to the interface circuit. The method also includes coupling a first type alarm indicator to the first type sensor, and coupling a transmitter to the interface circuit to generate a first type signal in response to a first type alarm event detected by the first type sensor, the first type signal being receivable by at least one other hazard alarm connected thereto, to trigger a first type alarm indicator therein, while not triggering any second type alarm indicator connected thereto. A signal receiver is operatively coupled to the interface circuit to receive first type signals and second type signals, and to selectively actuate and not actuate the first type alarm indicator upon respective receipt thereof.
In yet a further aspect, this invention includes a method for upgrading an existing smoke alarm system, having a plurality of smoke alarms electrically connected to one another. The method includes providing a plurality of carbon monoxide alarms, each of the carbon monoxide alarms including an interface circuit coupled to an interconnect port to transmit and receive information with other hazard alarms interconnected thereto. The method further includes configuring the carbon monoxide alarms to trigger an alarm indicator in at least one other of the plurality of carbon monoxide alarms in response to an alarm event, while not triggering an alarm indicator in any of the plurality of smoke alarms; and electrically coupling the plurality of carbon monoxide alarms to the smoke alarm system.